Dehumidifying unit, layered temperature control dehumidifying element, drying device and method for temperature controlling the same

ABSTRACT

A dehumidifying unit, a layered temperature control dehumidifying element, a drying device and a temperature control method thereof are provided. The dehumidifying element has a plurality of dehumidifying units. The dehumidifying units are made of a direct heating desorption material and used for dehumidifying air by adsorption and capable of being regenerated by desorption. By performing temperature compensation through a preheater and performing a layered temperature control method on the dehumidifying element, the disclosure achieves a uniform temperature control on the air flow passage of the dehumidifying element so as to improve regeneration performance of the dehumidifying element and reduce energy consumption of the drying device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claimed priority to Taiwanese Patent Application No.103129312, filed on Aug. 26, 2014. The entirety of the above-mentionedpatent application is hereby incorporated by reference herein and made apart of this specification.

BACKGROUND DISCLOSURE

1. Technical Field Disclosure

The present disclosure relates to a dehumidifying unit, a layeredtemperature control dehumidifying element, a drying device and atemperature control method thereof.

2. Description of Related Art

As industrial manufacturing processes are developed toward a trend ofhigh automation and high precision, manufacturing spaces and devicesrequire high-quality air to ensure a high yield. Therein, humidity ofcompressed air is an important factor influencing a variety ofprocesses. Therefore, humidity control has become an important researchtopic.

Generally, a conventional adsorption type compressed air drying devicehas two adsorption towers for adsorbing moisture of compressed air. Anadsorbent, such as silica gel, zeolite or activated carbon, is filled inthe adsorption towers. The adsorbent is used for dehumidifying air byadsorption and capable of being regenerated by desorption. Aftercompressed air having a high moisture content enters into one of theadsorption towers through pipelines, the moisture content is adsorbed todehumidify the compressed air. Then, the dehumidified compressed air isdirected to a reservoir for storage. Further, when the adsorption towerreaches a saturated adsorption, a heater is generally used to heat theadsorbent inside the adsorption tower to desorb moisture from theadsorbent and regenerate the adsorbent. To perform the moisturedesorption and adsorbent regeneration process, air to be used for theprocess is first heated by radiation, convection or heat and masstransfer to a moisture desorption temperature and then introduced intothe adsorption tower for moisture desorption and adsorbent regeneration.After the process, the compressed air with high temperature and highhumidity is discharged out of the adsorption tower, and the adsorbent isready for another air dehumidifying process.

However, during transmission of the hot air to be used for the moisturedesorption and adsorbent regeneration process, heat and mass transfereasily occurs between the hot air and pipeline walls, thus causing anenergy loss. Further, during the moisture desorption and adsorbentregeneration process, heat is transmitted to the adsorbent by hot airconvection. As such, a non-uniform temperature distribution easilyoccurs. For example, the temperature at the hot air inlet port ishighest and the temperature at the outlet port is lowest, therebyprolonging the regeneration time. Furthermore, during the heatingprocess, lower-temperature waste air must be discharged first, thusincreasing the energy consumption of the conventional adsorption typecompressed air drying device.

Therefore, how to overcome the above-described drawbacks has becomecritical.

SUMMARY DISCLOSURE

In view of the above-described drawbacks, the present disclosureprovides a dehumidifying unit, which comprises: an upper frame and alower frame each having a plurality of rib portions, wherein a gap isformed between any adjacent two of the rib portions; a plurality ofupper screw bolts and lower screw bolts fixed to the upper frame and thelower frame, respectively; a direct heating desorption material wound onthe rib portions of the upper frame and the lower frame alternately toform a passage therebetween, wherein the direct heating desorptionmaterial has a metal sheet therein between two desorption sides of thedirect heating desorption material; and two conductive platesconductively connected to portions of the metal sheet exposed from thetwo desorption sides of the direct heating desorption material and fixedto the upper frame to form two electrodes.

The present disclosure further provides a layered temperature controldehumidifying element, which comprises: a plurality of dehumidifyingunits comprising a direct heating desorption material and used fordehumidifying air by adsorption and capable of being regenerated bydesorption, wherein the dehumidifying units are respectively disposed ina plurality of air chambers that are separated from one another by atleast a partition board, and through holes are formed between the airchambers to allow air to pass through and flow in parallel passages ofthe air chambers; a preheater disposed at an air inlet end of thelayered temperature control dehumidifying element to perform preheatingand temperature compensation on a first group of the dehumidifying unitsand thereby keep the first group of the dehumidifying units at a uniformtemperature for regeneration; a plurality of first temperature sensorsrespectively disposed at central positions of the dehumidifying units toperform temperature monitoring and feedback during regeneration of thedehumidifying units, wherein the first temperature sensors haveconnectors disposed at one side of the layered temperature controldehumidifying element; and a second temperature sensor disposed at anoutlet port of the preheater to perform temperature monitoring andfeedback when the preheater performs heating or temperaturecompensation.

The present disclosure further provides a layered temperature controlmethod for performing a uniform temperature control on a dehumidifyingelement of a direct heating desorption type drying device duringregeneration, which comprises the steps of: performing a heatingprocess, wherein a first dehumidifying unit of the dehumidifying elementis heated by a preheater and thereby a plurality of dehumidifying unitsconnected in series with the first dehumidifying unit are heated untilthe temperature of the dehumidifying element reaches a temperature rangefor regeneration; performing a temperature maintenance process, whereinheating is activated or stopped according to temperature variation ofthe individual dehumidifying units so as to maintain the regenerationtemperature within a tolerable range; and performing a cooling process,wherein the preheater is stopped from heating the dehumidifying unitsand cooling air is provided to accelerate cooling of the dehumidifyingelement.

The present disclosure further provides a direct heating desorption typedrying device, which comprises: an air inlet pipeline group; an airoutlet pipeline group positioned over the air inlet pipeline group; aplurality of direct heating desorption type drying components connectedin parallel, wherein, valves of the air inlet pipeline group and the airoutlet pipeline group are switched on/off to control air flowing intopressure tanks of the direct heating desorption type drying components,wherein each of the pressure tanks has a plurality of dehumidifyingelements and each of the dehumidifying elements has a preheater toperform preheating and temperature compensation on the dehumidifyingelement, the pressure tank has air inlet and outlet ports connected tothe air inlet and outlet pipeline groups, respectively, and the airflowing into the pressure tank is dehumidified by dehumidifying units ofthe dehumidifying elements of the pressure tank through adsorption or isused to regenerate the dehumidifying units by desorption; and a heatexchanger in communication with the air inlet pipeline group, the airoutlet pipeline group and the valves to condense high-temperaturehigh-humidity air after regeneration of the direct heating desorptiontype drying components and accelerate cooling of the dehumidifyingunits.

Therefore, the present disclosure uses a dehumidifying element made of adirect heating desorption material to dehumidify air. Particularly, byperforming preheating through a preheater and performing a layeredtemperature control method on the dehumidifying element, the presentdisclosure achieves a uniform temperature effect on the air flow passageof the dehumidifying element, thus improving regeneration performance ofthe dehumidifying element and reducing energy consumption.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C are schematic views of a layered temperature controldehumidifying element of the present disclosure;

FIGS. 2A to 2C are schematic views of a dehumidifying unit of thelayered temperature control dehumidifying element of the presentdisclosure;

FIG. 3 is a schematic process flow of a layered temperature controlmethod of the present disclosure;

FIG. 4 is a schematic view of a direct heating desorption type dryingdevice of the present disclosure; and

FIGS. 5A to 5C are schematic views of a direct heating desorption typedrying component of the direct heating desorption type drying device ofthe present disclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following illustrative embodiments are provided to illustrate thedisclosure of the present disclosure, these and other advantages andeffects can be apparent to those in the art after reading thisspecification.

It should be noted that all the drawings are not intended to limit thepresent disclosure. Various modifications and variations can be madewithout departing from the spirit of the present disclosure. Further,terms such as “on”, “a” etc. are merely for illustrative purposes andshould not be construed to limit the scope of the present disclosure.

FIGS. 1A to 1C are schematic views of a layered temperature controldehumidifying element 1 of the present disclosure. FIG. 1A shows anouter structure of the layered temperature control dehumidifying element1, FIG. 1B shows an inner structure of the layered temperature controldehumidifying element 1, and FIG. 1C shows a cross-sectional view of thelayered temperature control dehumidifying element 1.

Referring to FIGS. 1A to 1C, the layered temperature controldehumidifying element 1 has a plurality of dehumidifying units 10, apreheater 11, a plurality of first temperature sensor connectors 12, anda second temperature sensor connector 13.

Each of the dehumidifying units 10 includes a direct heating desorbingmaterial and is used for dehumidifying air by adsorption and capable ofbeing regenerated by desorption. The dehumidifying units 10 are disposedin a plurality of air chambers 150, respectively. The air chambers 150are separated from one another by at least a partition board 15 and athrough hole 151 is formed at a central position of the partition board15, thus allowing air to flow in parallel passages of the air chambers150.

The preheater 11 is disposed at an air inlet end of the layeredtemperature control dehumidifying element 1 to perform preheating andtemperature compensation on the dehumidifying units 10, thereby keepingthe dehumidifying units 10 at a uniform temperature for regeneration.

The first temperature sensor connectors 12 are connected to firsttemperature sensors (not shown). The first temperature sensors aredisposed at central positions of the dehumidifying units 10 to performtemperature monitoring and feedback during regeneration of thedehumidifying units 10. The first temperature sensor connectors 12 aredisposed at one side of the layered temperature control dehumidifyingelement 1. The second temperature sensor connector 13 is connected to asecond temperature sensor (not shown) that is disposed at an outlet portof the preheater 11 to perform temperature monitoring and feedback whenthe preheater 11 performs heating or temperature compensation. Thesecond temperature sensor connector 13 is disposed at one side of thelayered temperature control dehumidifying element 1.

In practice, the layered temperature control dehumidifying element 1 hasan outer structure as shown in FIG. 1A. Referring to FIG. 1A, thelayered temperature control dehumidifying element 1 has a side coverboard 141, a bottom board 142, an air inlet end board 143, an air outletend board 144, an upper cover board 145 and a preheater cover board 146.The components constitute a fixing frame of the layered temperaturecontrol dehumidifying element 1 and the inside of the fixing frame isseparated by the partition boards 15 into the air chambers for receivingthe dehumidifying units 10. As such, the layered temperature controldehumidifying element 1 has adsorption-based dehumidifying anddesorption-based regenerating functions. Referring to FIG. 1C, thepartition boards 15 have the through holes 151 that allow air to flowbetween the air chambers.

A preheater partition board 16 is provided and disposed in such a mannerthat an air chamber is formed between the preheater partition board 16and the air inlet end board 143. The preheater 11 is disposed in the airchamber to perform preheating and temperature compensation for thelayered temperature control dehumidifying element 1. The preheater 11is, for example, a positive temperature coefficient (PTC) resistor or acommon electric heating wire. The preheater partition board 16 has athrough hole 161 that allows air to pass through. Further, the air inletend board 143 has an air inlet port 1431 and the air outlet end board144 has an air outlet port 1441. If necessary, the air inlet end board143 has a gasket 1432 to ensure airtightness between the layeredtemperature control dehumidifying element 1 and the entire dehumidifyingcavity. The air outlet end board 144 can also have a gasket (not shown).

The first temperature sensors are disposed at central positions of thedehumidifying units 10 and the first temperature sensor connectors 12are fixed to one side of the frame of the layered temperature controldehumidifying element 1. The first temperature sensors performtemperature monitoring and feedback during regeneration of thedehumidifying units 10 of the layered temperature control dehumidifyingelement 1. The second temperature sensor is disposed on the bottom board142 close to the outlet port of the preheater 11 and connected to thesecond temperature sensor connector 13 to perform temperature monitoringand feedback when the preheater 11 performs heating or temperaturecompensation. Further, the layered temperature control dehumidifyingelement 1 has a logic control circuit (not shown) connected to thepreheater 11, the first temperature sensor connectors 12 and the secondtemperature sensor connector 13 to achieve a uniform temperature controlon the dehumidifying units 10, which will be detailed later.

In order to supply power to the dehumidifying units 10 for regeneration,electrode screw sets 1451 are provided and connected to conductiveplates (not shown) of the dehumidifying units 10 inside the layeredtemperature control dehumidifying element 1. Similarly, in order tosupply power to the preheater 11 for heating, electrode screw sets 1461are provided and connected to power lines of the preheater 11 inside thelayered temperature control dehumidifying element 1.

FIGS. 2A to 2C show disposing of the direct heating desorption materialin the dehumidifying units of the layered temperature controldehumidifying element 1 according to the present disclosure. FIG. 2Ashows an overall structure of a dehumidifying unit 2 (i.e., one of thedehumidifying units 10 of FIGS. 1A to 1C), FIG. 2B shows a front view ofthe dehumidifying unit 2, and FIG. 2C shows an upper frame of thedehumidifying unit 2.

Referring to FIGS. 2A to 2C, an upper frame 22 and a lower frame 23 areprovided to fix a direct heating desorption material 21. The upper frame22 and the lower frame 23 are tension-adjustable. Each of the upperframe 22 and the lower frame 23 has a plurality of rib portions 221 anda gap 222 is formed between any adjacent two of the rib portions 221.The direct heating desorption material 21 is wound back and forth in aU-shape on the rib portions 221 of the upper frame 22 and the lowerframe 23 with a preferred gap of 1 to 10 mm The direct heatingdesorption material 21 has a metal sheet therein between two desorptionsides of the direct heating desorption material. Portions of the metalsheet between the two desorption sides of the direct heating desorptionmaterial 21 are exposed and fixed by conductive plates 26, respectively,thus allowing current to flow into the direct heating desorptionmaterial 21 for direct heating desorption and regeneration. Regardingthe detailed description of the direct heating desorption material, itcan be referred to U.S. Pat. No. 8,747,528 issued Jun. 10, 2014 which isexpressly incorporated by reference herein in its entirety and for allpurposes.

In practice, the upper frame 22, the lower frame 23, a plurality oflower screw bolts 24 and a plurality of upper screw bolts 25 constitutea frame of the dehumidifying unit 2. In particular, the rib portions 221of the upper frame 22 and the lower frame 23 serve as supporting andseparating means. The direct heating desorption material 21 is passedthrough the gaps 222 and wound back and forth in a U-shape on the upperframe 22 and the lower frame 23, thus forming a plurality of parallelpassages 211 therein and reducing component damage, as shown in FIG. 2B.

The direct heating desorption material 21 is stretched and tightened byrotating the upper screw bolts 25 and the lower screw bolts 24.Thereafter, the portions of the metal sheet between the two desorptionsides of the direct heating desorption material 21 and the correspondingconductive plates 26 are fixed to the upper frame 22 by screw sets 261to form two electrodes. Electrode screw holes 27 are formed on theconductive plates 26 and engaged with the electrode screw sets 1451 ofFIG. 1A so as to guide current into the conductive plates 26 forregeneration. Further, an airtight foam (not shown) can be attached tothe inlet and outlet ports of the dehumidifying unit 2 to improve theairtight effect.

Therefore, a preheater is used to achieve a uniform temperature effecton air passages of a layered temperature control dehumidifying element,thereby improving the desorption-based regeneration effect. Inparticular, to achieve the uniform temperature effect, a logic controlcircuit determines to perform a heating process, a cooling process or atemperature maintenance process according to a temperature sensingresult.

Accordingly, the present disclosure provides a layered temperaturecontrol method to achieve a uniform temperature control on dehumidifyingelements of a direct heating desorption type drying device. The methodcan perform a heating process, a cooling process and a temperaturemaintenance process.

During the heating process, a first dehumidifying unit of adehumidifying element as well as a plurality of dehumidifying units inseries connection with the first dehumidifying unit are heated by apreheater until the temperature reaches a temperature range forregeneration. Then, the heating process is stopped and the temperaturemaintenance process is performed. That is, if the dehumidifying elementdoes not reach the specified temperature for regeneration, the preheateris activated to heat the dehumidifying units. Generally, the temperaturerange for regeneration is between 80 and 160. The temperaturemaintenance process is not performed until the dehumidifying elementreaches the specified temperature range for regeneration.

During the temperature maintenance process, heating is activated orstopped according to temperature variation of the individualdehumidifying units so as to maintain the regeneration temperaturewithin a tolerable range. Further, during the cooling process, thepreheater is stopped from heating the dehumidifying units and coolingair is provided to accelerate cooling of the dehumidifying element.

A complete process flow for temperature control is detailed as follows.

FIG. 3 shows a process flow of the layered temperature control method ofthe present disclosure. Referring to FIG. 3, a layered temperaturecontrol dehumidifying element 31 and a logic control circuit 32 areshown. The layered temperature control dehumidifying element 31 has apreheater 311 and a plurality of dehumidifying units 312. The preheater311 is used to provide heat for preheating and temperature compensationof the layered temperature control dehumidifying element 31. Thedehumidifying units 312 are made of a direct heating desorption materialso as to provide adsorption-based dehumidifying and desorption-basedregenerating functions.

The logic control circuit 32 can perform a heating process 321, atemperature maintenance process 322 and a cooling process 323.

The heating process 321 provides a heating signal when the layeredtemperature control dehumidifying element 31 is to perform adesorption-based regenerating process. The heating signal activates thepower source through a heating control circuit 3211 so as to cause thepreheater 311 to heat the dehumidifying units 312. Temperature signalsof the dehumidifying units 312 are sent to a temperature feedbackprocessor 324 through a temperature feedback circuit 3212 so as for adetermining process to be performed. If the temperature reaches therequired regeneration temperature, the power source is switched off tostop heating the dehumidifying units 312, and an air flow is activatedso as for the layered temperature control dehumidifying element 31 toperform the desorption-based regenerating process. When the temperatureis lower than the required regeneration temperature, the temperaturefeedback processor 324 activates the temperature maintenance process 322to allow the preheater 311 to make temperature compensation for thedehumidifying units 312 by intermittently switching on/off the powersource. The heating time is adjusted according to the signal of thetemperature feedback circuit 3212. As such, the overall flow passage ofthe layered temperature control dehumidifying element 31 is maintainedat a constant regeneration temperature.

Further, the regeneration process of the layered temperature controldehumidifying element 31 is stopped through humidity control. A humiditysignal from a humidity sensor mounted to a last group of thedehumidifying units 312 is sent through a humidity signal circuit 3215to a humidity feedback processor 326. If it is determined that thehumidity reaches a predefined humidity value, a cooling processor 325 isactivated to perform the cooling process, which includes switching offthe preheater 311 and stopping heating the dehumidifying units 312 andstopping supplying air for regeneration. Further, a cooling air can beprovided for the cooling process so as to accelerate cooling of thelayered temperature control dehumidifying element 31 and facilitateanother adsorption-based dehumidifying process. Otherwise, if thelayered temperature control dehumidifying element 31 has a hightemperature, moisture adsorption will be adversely affected.

By using hardware, such as a PLC (programmable logic controller) or apersonal computer, the logic control circuit 32 can control thedesorption-based regenerating process of the layered temperature controldehumidifying element 31 through a transmission interface.

FIG. 4 is a schematic view of a direct heating desorption type dryingdevice of the present disclosure. Referring to FIG. 4, the directheating desorption type drying device 4 has two direct heatingdesorption type drying components 41A, 41B, an air inlet pipeline group42, an air outlet pipeline group 43, and a heat exchanger 44. The airoutlet pipeline group 43 is positioned over the air inlet pipeline group42. Generally, one of the direct heating desorption type dryingcomponents 41A, 41B performs a dehumidifying process while the otherperforms regenerating by desorption. Air can be controlled to flow intoeither of the direct heating desorption type drying components 41A, 41Bthrough valves or switches.

In particular, the direct heating desorption type drying components 41A,41B are connected to the air inlet pipeline group 42 and external air isallowed to enter into the direct heating desorption type dryingcomponents 41A, 41B through pipelines 421 for dehumidifying orregenerating. By switching on/off valves 423, external humid air can beguided into the direct heating desorption type drying component 41A or41B for a dehumidifying process. By switching on/off valves 422,condensed air with lower temperature and low humidity from the heatexchanger 44 or external air can be guided into the direct heatingdesorption type drying component 41A or 41B for regeneratingdehumidifying elements. Further, by switching on/off valves 424,moisture remaining on the bottom of the direct heating desorption typedrying component 41A or 41B can be discharged.

The direct heating desorption type drying components 41A, 41B can changebetween dehumidifying and regenerating processes by alternatelyswitching on/off valves 432, 433. Therein, when the direct heatingdesorption type drying component 41A performs a dehumidifying process,the valves 432, 423 on the upper and lower sides thereof are switched onand the valve 433 on the upper side thereof and the valve 423 on thelower side of the direct heating desorption type drying component 41Bare switched off. After the dehumidifying process, dehumidified air canbe guided into a reservoir for storage. Further, when the direct heatingdesorption type drying component 41B performs regenerating bydesorption, the valves 433, 422 on the upper and lower sides thereof areswitched on, and the valve 432 on the upper side thereof and the valve422 on the lower side of the direct heating desorption type dryingcomponent 41A are switched off. High-temperature high-humidity air afterthe regenerating process can be guided into the heat exchanger 44through pipelines 442 and condensed into low-temperature low-humidityair that is further guided into the direct heating desorption typedrying component 41B for regeneration. Alternatively, thehigh-temperature high-humidity air generated after the process can bedischarged through pipelines 431. When the drying device stopsoperation, switches 424 below the direct heating desorption type dryingcomponent 41A or 41B and the heat exchanger 44 can be turned on todischarge condensed liquid.

The direct heating desorption type drying components 41A, 41B can changebetween dehumidifying and regenerating processes by alternatelyswitching on/off the valves 432, 433. When a valve 432 is switched on,dehumidified air after the dehumidifying process of the correspondingdirect heating desorption type drying component is guided through thepipelines 431 to a reservoir for storage. In addition, if a valve 433 isswitched on, high-temperature high-humidity air after the regeneratingprocess of the corresponding direct heating desorption type dryingcomponent is guided into the heat exchanger 44 through the pipelines 442for moisture condensation.

Condensed low-temperature air is guided through pipelines 441 into thedirect heating desorption type drying component 41A or 41B again forregeneration. Further, air condensed by the heat exchanger 44facilitates to accelerate cooling of the dehumidifying elements of thedirect heating desorption type drying component 41A or 41B, thusshortening the regenerating process and allowing the dehumidifyingelements to be quickly ready for another dehumidifying process.

In particular, the direct heating desorption type drying components 41A,41B are connected in parallel. The valves on the air inlet pipelinegroup 42 and the air outlet pipeline group 43 are switched on/off tocontrol inlet of air into a pressure tank of the direct heatingdesorption type drying component 41A, 41B. The pressure tank has aplurality of dehumidifying elements arranged in an array. Each of thedehumidifying elements has a preheater for performing preheating andtemperature compensation on the dehumidifying element. Air inlet andoutlet ports of the pressure tank are connected to the air inletpipeline group 42 and the outlet pipeline group 43, respectively. Air issent into the pressure tank so as to be dehumidified by dehumidifyingunits of the dehumidifying elements or used for regeneration of thedehumidifying units. The inner structure of the direct heatingdesorption type drying component 41A, 41B will be detailed later.

Further, the direct heating desorption type drying device 4 can have afixing member (not shown) for fixing the air inlet pipeline group 42,the air outlet pipeline group 43 and the direct heating desorption typedrying components 41A, 41B.

FIGS. 5A to 5C are schematic views of a direct heating desorption typedrying component of the direct heating desorption type drying device.FIG. 5A shows an outer structure of the direct heating desorption typedrying component 51 (i.e., the direct heating desorption type dryingcomponent 41A or 41B of FIG. 4), FIG. 5B shows a cross-sectional view ofthe direct heating desorption type drying component 51, and FIG. 5Cshows layered temperature control dehumidifying elements inside thedirect heating desorption type drying component 51.

The direct heating desorption type drying component 51 has a base body511, an air inlet hopper 512, and an air outlet hopper 513. The basebody 511 is fixed to the frame of the direct heating desorption typedrying device 4 through a holding member 5111. A connection plate 5112is disposed at one side of the base body 511. The connection plate 5112is detachable from the base body 511 so as to facilitate mounting of thedehumidifying elements 1 inside the base body 511. The connection plate5112 further has a plurality of temperature connector groups 5112Aconnected to the temperature sensor groups of the layered temperaturecontrol dehumidifying elements 1. Furthermore, the connection plate 5112has power connector groups 5112B connected to the dehumidifying unitsand preheaters of the layered temperature control dehumidifying elements1 so as to supply power to the layered temperature control dehumidifyingelements 1.

The base body 511 has a base board 5113 disposed at the bottom air inletend and a cover board 5114 disposed at the top air outlet end. Duringassembly, the layered temperature control dehumidifying elements 1 canbe closely arranged with gaskets that are provided on upper and lowerends thereof for positioning and airtightness. The air inlet end of thebase body 511 is connected to the air inlet hopper 512. The air inlethopper 512 has an air inlet port 5121 connected to air inlet pipelinesfor guiding air into the base body 511. Further, the air inlet hopper512 has an orifice plate 5122 and a diffusion net 5123. The orificeplate 5122 has a large-sized orifice and the diffusion net 5123 has asmall-sized hole so as to facilitate uniform diffusion of air andimprove the efficiency of contact between the air and dehumidifyingelements.

The air outlet end of the base body 511 is connected to an air outlethopper 513. The air outlet hopper 513 has an air outlet port 5131connected to air outlet pipelines so as to guide air after adehumidifying or regenerating process out of the base body 511. Further,the air outlet hopper 513 has a filtering net 5133 and an orifice plate5132 disposed therein for filtering out dust and impurity and clean theair. The layered temperature control dehumidifying elements 1 arearranged in an array inside the base body 511.

Therefore, the present disclosure provides a dehumidifying unit, alayered temperature control dehumidifying element, a drying device and alayered temperature control method. By performing preheating through apreheater and performing the layered temperature control method on thedehumidifying element, the present disclosure achieves a uniformtemperature effect on the air flow passage of the dehumidifying element,thus improving regeneration performance of the dehumidifying element andreducing energy consumption.

The above-described descriptions of the detailed embodiments are only toillustrate the preferred implementation according to the presentdisclosure, and it is not to limit the scope of the present disclosure.Accordingly, all modifications and variations completed by those withordinary skill in the art should fall within the scope of presentdisclosure defined by the appended claims.

What is claimed is:
 1. A layered temperature control method forperforming a uniform temperature control on a dehumidifying element of adirect heating desorption type drying device during regeneration,comprising the steps of: performing a heating process, wherein a firstdehumidifying unit of the dehumidifying element is heated by a preheaterand thereby a plurality of dehumidifying units connected in series withthe first dehumidifying unit are heated until the temperature of thedehumidifying element reaches a temperature range for regeneration;performing a temperature maintenance process, wherein heating isactivated or stopped according to temperature variation of theindividual dehumidifying units so as to maintain the regenerationtemperature within a tolerable range; and performing a cooling process,wherein the preheater is stopped from heating the dehumidifying unitsand cooling air is provided to accelerate the cooling of thedehumidifying element.
 2. The method of claim 1, further comprisingmounting a humidity sensor to a last group of dehumidifying units forsensing air humidity and generating a humidity signal, thus allowing thecooling process to be performed when the air humidity is below apredefined humidity value.
 3. A direct heating desorption type dryingdevice, comprising: an air inlet pipeline group; an air outlet pipelinegroup positioned over the air inlet pipeline group; a plurality ofdirect heating desorption type drying components connected in parallel,wherein, valves of the air inlet pipeline group and the air outletpipeline group are switched on/off to control air flowing into pressuretanks of the direct heating desorption type drying components, whereineach of the pressure tanks has a plurality of dehumidifying elements andeach of the dehumidifying elements has a preheater to perform preheatingand temperature compensation on the dehumidifying element, the pressuretank has air inlet and outlet ports connected to the air inlet andoutlet pipeline groups, respectively, and the air flowing into thepressure tank is dehumidified by dehumidifying units of thedehumidifying elements of the pressure tank through adsorption or isused to regenerate the dehumidifying units by desorption; and a heatexchanger in communication with the air inlet pipeline group, the airoutlet pipeline group and the valves to condense high-temperaturehigh-humidity air after regeneration of the direct heating desorptiontype drying components and accelerate cooling of the dehumidifyingunits.
 4. The device of claim 3, wherein the pressure tank further has abase body, an air inlet hopper having an air inlet orifice plate and adiffusion net that allow air to uniformly flow into the dehumidifyingelements, and an air outlet hopper having a filtering net and an airoutlet orifice plate for filtering out dust and impurity in the air. 5.The device of claim 4, wherein the pressure tank has a connection platedisposed at one side of the base body to facilitate mounting of thedehumidifying elements, and the connection plate further has temperatureconnector groups connected to temperature sensor groups of thedehumidifying elements in the base body and power connector groupsconnected to the dehumidifying elements and the preheaters in the basebody to supply power to the dehumidifying elements and the preheaters.6. The device of claim 5, wherein the temperature sensor groups and thepreheaters are connected to a logic control circuit to achieve a uniformtemperature control on the dehumidifying elements.
 7. The device ofclaim 3, wherein the dehumidifying elements are arranged in an array inthe pressure tank.
 8. The device of claim 3, wherein the direct heatingdesorption type drying components change between dehumidifying andregenerating processes by alternately switching on/off two or morevalves.
 9. The device of claim 3, wherein each of the dehumidifyingelements is a layered temperature control dehumidifying element,comprising: a plurality of dehumidifying units comprising a directheating desorption material and used for dehumidifying air by adsorptionand capable of being regenerated by desorption, wherein thedehumidifying units are respectively disposed in a plurality of airchambers that are separated from one another by at least a partitionboard, and through holes are formed between the air chambers to allowair to pass through and flow in parallel passages of the air chambers,and wherein the preheater is disposed at an air inlet end of the layeredtemperature control dehumidifying element to perform preheating andtemperature compensation on a first group of the dehumidifying units andthereby keep the first group of the dehumidifying units at a uniformtemperature for regeneration; a plurality of first temperature sensorsrespectively disposed at central positions of the dehumidifying units toperform temperature monitoring and feedback during regeneration of thedehumidifying units, wherein the first temperature sensors haveconnectors disposed at one side of the layered temperature controldehumidifying element; and a second temperature sensor disposed at anoutlet port of the preheater to perform temperature monitoring andfeedback when the preheater performs heating or temperaturecompensation.
 10. The device of claim 9, further comprising a logiccontrol circuit connected to the preheater, the first temperaturesensors and the second temperature sensor to perform a uniformtemperature control on the dehumidifying units.
 11. The device of claim9, wherein the direct heating desorption material is fixed to each ofthe dehumidifying units by a tension-adjustable frame, and the directheating desorption material is passed through gaps between rib portionsof the frame so as to be wound back and forth in a U-shape on the ribportions of the frame.
 12. The device of claim 9, further comprising afixing frame having a side cover board, a bottom board, an air inlet endboard, an air outlet end board, an upper cover board and a preheatercover board, the inside of the fixing frame is separated by thepartition boards into the air chambers for receiving the dehumidifyingunits.
 13. The device of claim 12, wherein two ends of the directheating desorption material are conductively connected to conductiveplates, respectively, and electrode screw holes are formed in theconductive plates and engaged with electrode screw sets of the uppercover board so as to allow current to flow into the conductive platesfor regeneration of the direct heating desorption material.
 14. Thedevice of claim 9, wherein each of the dehumidifying units furthercomprising: an upper frame and a lower frame each having a plurality ofrib portions, wherein a gap is formed between any adjacent two of therib portions; a plurality of upper screw bolts and lower screw boltsfixed to the upper frame and the lower frame respectively, wherein thedirect heating desorption material is wound around the rib portions ofthe upper frame and the lower frame alternately to form a passagetherebetween, and wherein the direct heating desorption material has ametal sheet therein between two desorption sides of the direct heatingdesorption material; and two conductive plates conductively connected toportions of the metal sheet exposed from the two desorption sides of thedirect heating desorption material and fixed to the upper frame to formtwo electrodes.
 15. The device of claim 14, wherein the direct heatingdesorption material is passed through the gaps between the rib portionsof the upper frame and the lower frame.
 16. The unit of claim 14,wherein the direct heating desorption material is stretched andtightened by rotating the plurality of upper screw bolts and lower screwbolts.
 17. The unit of claim 14, wherein the two conductive plates andthe corresponding portions of the metal sheet are fixed to the upperframe by screw sets, and an electrode screw hole is formed in each ofthe conductive plates to allow current to flow into the conductiveplates.
 18. The unit of claim 14, wherein the portions of the metalsheet between the two desorption sides of the direct heating desorptionmaterial are exposed and fixed by conductive plates, respectively. 19.The unit of claim 14, wherein the direct heating desorption material iswound back and forth in a U-shape.
 20. The unit of claim 19, wherein thepassage formed therebetween is of a width of 1 to 10 mm.